The present invention relates to extracts of aquatic organisms, and, more particularly, to the use of same for the prevention of cell adhesion.
Microorganisms can live and proliferate as individual cells swimming freely in the environment (as plankton), or they can grow as highly organized, multicellular communities encased in a self-produced polymeric matrix in close association with surfaces and interfaces. The latter microbial lifestyle is referred to as biofilms. Biofilm formation represents an ancient, protected mode of growth that allows microbial survival in hostile environments and allows microorganisms to disperse and colonize new niches [Hall-Stoodley et al., Nat Rev Microbiol. (2004) 2(2):95-108].
The composition of biofilms is complex and variable among different microbial species and even within the same species under different environmental conditions. Nonetheless, biofilm formation represents the normal lifestyle of microorganisms in the environment, and all microbes can make biofilms. Previous studies revealed that bacterial biofilm formation progresses through multiple developmental stages differing in protein profiles [Sauer et al., J Bacteriol. (2002) 184(4):1140-54], beginning with attachment to a surface, followed by immigration and division to form microcolonies, and finally maturation, involving expression of matrix polymers. Bacteria within each biofilm stage display phenotypes and possess properties that are markedly different from those of the same group growing planktonically [Sauer et al., J Bacteriol. (2004) 186(21):7312-26].
Biofilms are a major cause of systemic infections (e.g., nosocomial infections) in humans. In the body, biofilms can be associated with tissues (e.g., inner ears, teeth, gums, lungs, heart valves and the urogenital tract). An estimated 65% of bacterial infections in humans are biofilm in nature. Additionally, after forming biofilms, microorganisms tend to change their characteristics, sometimes drastically, such that doses of antibiotics which normally kill the organisms in suspended cultures are completely ineffective against the same microorganisms when the organisms are in attached or conglomerate biofilm form (U.S. Pat. No. 7,189,351).
One of the principal concerns with respect to products that are introduced into the body (e.g., contact lenses, central venous catheters, mechanical heart valves and pacemakers) or provide a pathway into the body is microbial infection and invariably biofilm formation. As these infections are difficult to treat with antibiotics, removal of the device is often necessitated, which is traumatic to the patient and increases the medical cost. Accordingly, for such medical apparatuses, the art has long sought means and methods of rendering those medical apparatuses and devices antimicrobial.
Previous reports have shown that in the marine environment, many soft bodied marine invertebrates such as sponges [Amade et al., Mar. Biol. (1987) 94: 271-275; Wilsanand et al., Ind. J. Mar. Sci (1999) 28:274-279], ascidians [Wahl et al., Mar. Ecol. Prog. Ser (1994) 110:45-57], and soft corals [Aceret et al., Comp. Biochem. Phys (1998) 120:121-126; Kelman et al., Mar. Ecol. Prog. Ser (1998) 169:87-95], produce secondary metabolites that exhibit antibacterial and antifungal activities [Harder et al., FEMS Microbiology Ecology (2003) 43(3):337-347]. Additionally, sea anemones (e.g., Actinia equina) have been shown to produce toxic, pore forming peptides belonging to the actinoporin family, termed equinatoxins [Kristan et al., J Biol. Chem. (2004) 279(45):46509-17]. Equinatoxins (i.e., equinatoxin 1, 2 and 3), have been purified by acetone precipitation, Sephadex G-50, CM-cellulose and CM-Sephadex column chromatography from the tentacles and bodies of the sea anemone Actinia equine [Macek P and Lebez D., Toxicon. (1988) 26(5):441-51]. These toxic proteins lyse and kill eukaryotic cells by forming toroidal protein-lipid pores in target cell membranes similarly to other small antimicrobial peptides [Anderluh et al., J. Biol. Chem. (2003) 278(46):45216-45223].
Since marine-aquatic plants and animals are continuously exposed to a large diversity and abundance of potentially harmful microorganisms in the form of biofilm, and it is known that marine life produce anti-microbial peptides, it is possible that broad spectrum natural factors that interfere with biofilm formation may also be present in marine life.
U.S. Publication No. 20070098745 discloses means of preventing biofilm formation by the use of reef fish microflora. This invention describes anti-biofilm substances derived from bacteria isolated from the epithelial mucosal surfaces of healthy coral reef fish (e.g., Sparisoma ninidae and Lutjanus purpureus). The bacterial isolates produce signals or toxins that prevent biofilm formation.
Due to the preponderance of biofilms and their deleterious effects, there remains a widely recognized need for, and it would be highly advantageous to identify novel anti-biofilm agents.